[cipd] Rename new Root terminology to Subdir.

cipd/client/cmd/cipd/main.go

Index: cipd/client/cmd/cipd/main.go
diff --git a/cipd/client/cmd/cipd/main.go b/cipd/client/cmd/cipd/main.go
index 2a9a7614f89e98806b8ed80fd4e56396f8a958e8..54b973d0b5670747ecb385fbfd805feaacc202f0 100644
--- a/cipd/client/cmd/cipd/main.go
+++ b/cipd/client/cmd/cipd/main.go
@@ -767,17 +767,17 @@ func ensurePackages(ctx context.Context, root string, desiredStateFile string, d
 		return nil, cipd.Actions{}, err
 	}
 
-	baseRoot := resolved.PackagesByRoot[""]
-	delete(resolved.PackagesByRoot, "")
-	if len(resolved.PackagesByRoot) > 0 {
-		return nil, cipd.Actions{}, errors.New("@Root not yet supported")
+	baseSubdir := resolved.PackagesBySubdir[""]
+	delete(resolved.PackagesBySubdir, "")
+	if len(resolved.PackagesBySubdir) > 0 {
+		return nil, cipd.Actions{}, errors.New("@Subdir not yet supported")
 	}
 
-	actions, err := client.EnsurePackages(ctx, baseRoot, dryRun)
+	actions, err := client.EnsurePackages(ctx, baseSubdir, dryRun)
 	if err != nil {
 		return nil, actions, err
 	}
-	return baseRoot, actions, nil
+	return baseSubdir, actions, nil
 }
 
 ////////////////////////////////////////////////////////////////////////////////